Mar 15, 2018

Full Disclosure

The evolution of Lil Bud has been an open book. So as not to clog up the Lil' Bud thread on I'll break down the current build process in some quite boring detail.

Local Lumber Yard
All LB's start as a piece of Cherry or Walnut wood. I shop at a really cool specialty hardwood lumber yard, Urban Hardwoods. I haven't found anything like it in my area (New York City / Long Island). You can walk in, pick through boards of all kinds of stuff. That's why it works for me, I can hand pick my pieces. I usually wind up with a couple of 6 to 8 foot boards that are about an inch and half thick by seven inches wide. I have them square up all four sides (S4S), makes a bit easier to dive right into vape building vs milling lumber.

First stop, the most important machine in any wood shop, the tablesaw. I crosscut the large boards to manageable sizes, from 2 to 4 feet, depending upon what's going on with the wood grain. Next I rip them all to the 58mm width and finally, they're cut to 28mm thick (left a hair big for finishing). I take my 2 to 4 foot boards and do a rough layout of mortises (square recess for the battery). I'll normally get 3 or 4 Lil' Buds from every 2 foot board.

At this point I also pick out wood for the switchbox, some will be matching and taken from the same board as the unit, others will feature contrasting woods. I make sure I cut extra stock for the switchbox to thickness and width (a hair big). I won't cut switchboxes to length until I make the final fit to each unit.

Next I cut the mortises with a hand held trim / plunge router and a spiral upcut bit. The mortise is the first extreme need for total accuracy or the battery won't sit in there just right, with just the right pressure on the contacts. I have a jig built to cut pretty accurate mortises with very little set up after the initial work.   Consistency is the only way to ensure accuracy.  After the initial set up, I only have to move the work and clamp. Once the work is secured, it's never moved. The router cuts the mortise in 6 passes, and I never have to touch the router (shimming is the secret).

Mortises are far from done. Each one has to be squared up by hand with a chisel / file, sandpaper. That can take as long as routing out the mortise. The mortise will go through at least three separate rounds of being squared up and made as perfect as possible.

Back Plate Slot / Round Edges / Cut to Length
Now it's time for the back plate groove, or where the slot the back plate drops into. This time, we'll work on the router table. After careful set up of the bit height and fence, we're ready to run all boards through from both sides (symmetry).  Now  I change bits and round all four edges.

You have to cut the units to exact length from the 2 foot boards of 4 units. What is vital, is the measurement from the top of the mortise to the end of the unit, not just length. So I built a little jig that clamps onto the mortise and give me the perfect dimension from mortise edge to LB top and bottom. This is the surface that will house the super powerful 6mm magnets.

Drill-a-thon / Switchbox Cutout
The first hole that forms the tapered bowl is drilled next. I lay out all units for the center point of that hole. A 5/8 hole is drilled into all units before the switch box is cut out for.  Then it's back to the tablesaw to the second super critical task, cutting out for the switchbox. I have a simple fence on my tablesaw miter gauge that makes the square cuts I need. Again, set up once cut 10 or 15 times. I need to make two perfect 90 degree cuts that form the cutout of the switchbox. Once all are cut, and it takes a while because these cuts need to be as clean as possible. Each cut has to be hand finished with a chisel / file / sandpaper to square up. The entire LB will get another faring and sanding. This makes things come together much faster at the end.

Back to the drill press to drill the remain holes. First the reamer cuts the taper in the 5/8 hole from the top. This is an amazing tool! Next we drill the coil's housing from below. Finally, the hole for the disk is drilled out. The disk hole depth ultimately determines how close the heater is to the load. This has been and area of major improvement for LB.

Next, I drill out for the magnets and vent holes, and sand down to 400 grit, but before I can finish up in the wood shop, I have to build the switchboxes. For some units I use the wood adjacent to the wood that forms the LB body, so the round is already cut. For the contrasting units, I have a strip I cut to length. I leave all switchboxes a bit big so I can plane flat later.  I also have to drill out the switchboxes for the switch  and wires to the battery compartment and heater.

The final step in the wood shop is building the back plate and battery safety tab slot. Now it's time for the electronics. First I build all the coils.

The Art of Coil Building
So this is where it gets deep. Heat is generated by running current from an 18650 battery through a wire mesh coil. The mesh is very specific in size, gauge, number of squares, so as to create the perfect amount of resistance (where the heat comes from).  The mesh is about a half inch wide and a four inches long. It is attached to 18 gauge, silver plated, copper, stranded wire (19 strands of 30 awg) with uninsulated but splice connectors and silver solder. In addition, the wire is thoroughly *tinned* with silver solder from end to end, dramatically improving connectivity and strength, while maintaining the integrity of the wires during assembly and installation. This is one of the secrets that makes LB so efficient.

The process is to entailed to spell out here in every detail, but once connected you have a miniature tennis net that needs to be rolled into a perfect six layer single coil. One end post will be dead center, the other on the perimeter of the coil. A one inch wood disk is prepared for mounting the coil once formed. Forming the  perfectly straight, perpendicular, equidistant, aligned coil shape can be a challenge. Time, patience, and lots of trial and error are necessary to get that perfect coil mounted just right. During phase one of coil build, I'll take near perfect, and do the final adjustment upon installation into the unit. It can take almost a full day just to do all the prep work to form the coils for one batch, and then another day to actually build them, but once that is done, we're in the home stretch.

Mar 11, 2018

Negative Pressure and a Good Session

If you own an on demand vape, you're probably aware of draw *speed* and button depression, and it's affect on session control. But it's just about draw speed, which is definitely part of the equation, but about the POWER of the draw, or the negative pressure created when you put your lips on the stem and inhale.

You might not think about the seal your lips make with the stem, or how much air is allowed to leak in and reduce the level of suction created, but that doesn't mean it's not happening. Taking control of this powerful element of vaporizing will put you in the driver's seat.

A lot of variables come together when you draw, but how much negative pressure you create on the mouthpiece dominates what's going on in the herb. No matter how hot (or cold) that coil gets, without a seal, the heat will not reach the herb. On the other hand, reducing suction by just a hair, while coordinating with speed, will keep you from ever getting to the point of combustion

The flower puck should be the most resistive part of the system. The volume rate of air flow will depend upon how resistive the puck is and how much vacuum you are pulling. It is the volume rate that affects the rate at which the heat is removed from the coil. If you can't keep up with the rate of energy being added, the temperature will rise.

Lil' Bud is powerful AND unregulated, with very fast heat. To optimize control of your session, be aware of not just draw speed and button depression, but how tight a seal your lips are forming on the stem, as this will control how much hot air is pulled through the herb.